The footballer Ched Evans had much to say following his rape acquittal, and the weekend newspapers gave him a platform to say it. Now rape campaigners must come to terms with the legacy of his case. By clearing the way for two men to tell the jury they’d had sex with the complainant, the court of appeal effectively converted his earlier conviction into an acquittal. Some lawyers say this was a rare case and doubt that, as a precedent, it will affect many future cases. But other lawyers – and I am one of them – fear that rape trials could become inquisitions into the complainant’s sex life.

We seem to be returning to a mindset and practices we thought were confined to history. In seeking – as we now must – to find a new way forward, it’s worth recalling how we reached this point.

The fear of a complainant being confronted with evidence relating to sex with other men is, and has always been, a huge deterrent to reporting rape. In 1976 judges were given powers to prevent defence lawyers using that tactic, but the discretion they enjoyed was wide, unregulated and infrequently used. So a rape defendant could bring Mr B and Mr C to testify that the complainant had had consensual sex with them. The argument would run, she consented to me as well because she’ll have sex with anyone. The two arguments – she’s a tart and you can’t believe a word she says – were what women, not surprisingly, feared. These were the “twin myths” that flowed from the use of previous sexual history.

One in five trials sees an application for sexual history to be heard, even now

In 1999, the Labour government curtailed the use of complainants’ sexual conduct with other people as evidence of consent; but so entrenched was the perception among complainants that four years later a review of the legislation showed it was still a key factor in low reporting rates.

Whatever the truth of this kind of testimony, it was usually irrelevant to the charge itself. Lord Steyn, in the House of Lords case of R v A (No 2) referred to in Evans second appeal, said that: “Questioning and evidence about the complainant’s sexual experience with other men … are almost always irrelevant to the issue whether the complainant consented to sexual intercourse on the occasion alleged in the indictment or to her credibility.”

Yet as a tactic, it worked. Rape allegations judged strong enough to take to court by the Crown Prosecution Service were routinely lost. Brothers, cousins and men from the pub came to say they too had had sex with her. Jurors continually fell prey to the twin myths.

Campaigning for change in the late 90s, I wrote a pamphlet called Rape in Court and mentioned research by a Canadian academic who showed that the chances of a conviction in a rape trial were inversely proportional to the extent of sexual allegations made against a complainant. The more there was alleged, even if every bit of it was denied, the less the chance of a conviction. Add to that Lord Steyn’s view, and it is clear that many acquittals were gained by prejudice.

The clause utilised by lawyers for Evans was only added towards the end of the 1999 bill’s progress through parliament. It reversed the exclusion of sexual history evidence – if what the defendant alleged was sex between the complainant and another that was “so similar” to what was alleged in the rape that it could not be explained by coincidence. It has hardly ever been used.

The key case in which it was used concerned a couple having consensual sex, standing upright inside a children’s climbing frame. It was alleged that on a second such occasion, with the same partner, it was rape.

In Evans’ case, the court of appeal decided it “relevant and admissible” that the woman had had separate sexual encounters with two men, around the time of the alleged rape. On each occasion she had consumed a lot of alcohol, and had been enthusiastic, directing sexual events. She used similar words calling for more vigour from the male partner, and, once with each man, used a particular, though not uncommon, sexual position. Evans said she behaved similarly with him. Since this was presumably her typical conduct in consensual sex, it supported his case that she’d consented with him. But by any evaluation, these “similarities” are of a significantly lower scale than in the case of the climbing frame in terms of proving typical behaviour.

And therein lies the danger. Why wouldn’t most defendants, claiming consent, not check out the Evans defence? Why would they not seek to find out whether the woman has had sex with somebody else “similar” in style to that with the defendant? Evans had funding and private investigators. The current protections were not able to shield her and could be equally weak against a local search for witnesses and the do-it-yourself sleuthing that might be the poor man’s way. Consider the impact of such an intrusive investigation on the life of a complainant, and then her potential exposure to intimate questioning in court.

The potency of the “twin myths” is still well understood. One in five trials sees an application for sexual history to be heard, even now.

So is Evans’ case a rarity, or has the court, by lowering the bar of what is “admissible and relevant”, unintentionally lent itself to a potential return to the bad old days? If we are to not lose the recent upturn in rape reporting, and the slowly growing willingness of complainants to speak out, we must be vigilant. We fought to protect women from being unfairly judged on their sexual history. We may have to begin that fight again.